In the Mediterranean region of Turkey, strawberry production is a vital part of the agricultural sector, providing high rates of employment and farm income. Optimizing water application and effective cultivation practices are of considerable importance in improving strawberry yield. In this study the response of strawberry a cultivar (Fragaria ananassa Duch. cv. Rubygem) to irrigation regimes and bio-stimulant (seaweed extract) use were investigated, by evaluating the yield and morpho-physiological parameters under high tunnel conditions in the Mediterranean environment. The amounts of irrigation water applied were 0.50, 0.75, 1.00 and 1.25 times the water surface evaporation, measured by a standard Class A pan, and the corresponding regimes were denoted as 1r(50) , 1r(75), Ir-100, and Ir-125, respectively. There was a significant decrease in total berry yield and number of berries in the Ir-50 irrigation regime. The maximum total berry yield was attained at Ir 75 in both applications (585.7 g/plant and 521.9 g/plant under bio-stimulant and control applications, respectively). However, the results of Ir-75, Ir-100 and Ir-125 did not reveal any significant yield benefit. The bio-stimulant application provided a significant, 17% increase, in berry yield. The stomatal conductance and leaf water potential were reduced as irrigation application rates decreased. Conversely, stomatal conductance and leaf water potential were statistically higher, 41 mu mol.m(-2). s(-1) and 0.5 bar, respectively, after the use of the bio-stimulant, as it alleviated the negative effects of water stress. Bio-stimulant application also significantly increased fruit nitrogen content by approximately 14%. In conclusion, considering the irrigation regimes of strawberries grown under high tunnels in the Mediterranean environment, water use is recommended at around 274 mm (Ir-75), along with bio-stimulant application for optimal yield.